$WebClient = New-Object System.Net.WebClient

while(1){
    $Timestamp = [string][int][double]::Parse((Get-Date -UFormat %s));
    $WebClient.DownloadFile("https://api.whitehouse.gov/v1/petitions/2488296.json","C:\WhiteHouse\"+ $Timestamp + "_2488296.json")
    start-sleep -Seconds 60
}